Slits-loaded microstrip antennas for circular polarization

Novel diagonally slits-loaded compact microstrip antennas are proposed for circular polarization (CP). A group of four slits is loaded on the square patch radiator for compact antenna size with CP radiation. The slit with unequal sizes loaded on square patch in diagonal directions is used to achieve CP radiation. The combined V-shaped and square slits, diagonally loaded, microstrip antenna is compact when compared with V-shaped slits loaded microstrip antenna. The measured 10-dB return loss and 3-dB axial-ratio bandwidths are 3.55% and 0.82%, respectively, for a combined V-shaped and square slits loaded microstrip patch antenna. The overall size of the antenna is 0.256λ₀×0. 256λ₀×0.0136λ₀ at 2.55 GHz. The proposed slits-loaded patch radiator is useful for compact circularly polarized microstrip antenna and array designs.